Hi Zellene (and others),
I've followed the research literature on the effects of wind power on birds
quite closely. As an associate editor for the Journal of Applied Ecology (one
of the top scientific journals in the field) I've also handled a number of
papers on the topic ... there's an editorial I wrote, which summarizes some of
my thoughts about the state of research, here (it's a tad outdated, but mostly
holds true):
http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2664.2008.01579.x/pdf
I've not myself done much direct research on the topic, although I did conduct
one (very) small study in connection with a planned wind farm a few years ago
(full disclosure: it was funded by a wind power company ... but the entire grant
was only ~$5K, most of which went to supporting a student).
First, as others have said (perhaps more politely), it is nonsense to suggest
that wind turbines don't ever kill birds - there is ample evidence that they
do. On the other hand, so do cell phone towers, tall buildings, cars, oil rigs,
lighthouses, airplanes, and a multitude of other things that humans use.
Frankly, bird seed - which is grown as an agricultural crop, shipped half way
across continents, etc., etc. - probably kills a fair number of birds. So, as
someone who studies population ecology and conservation biology, I think that
the key question is not whether it kills birds but whether it kills enough to
affect the size of populations or cause a serious conservation threat -
especially relative to the alternative, which currently means more fossil fuel
use.
As Anthony mentioned there are some cases where this is a serious concern.
Golden eagles in California are the case that people typically cite, and there
have been real problems associated with some of the California wind farms. But,
those farms are some of the earliest built - and both the technology and
knowledge of how best to site and operate turbines has improved dramatically
over the past couple of decades. European studies (where the science is
strongest) have shown that most raptor mortality can be caused by a small number
of turbines within a wind farm, and mostly under quite specific wind
conditions/times of the year/day. One solution is improved siting, as Min
suggested. Another - especially relevant when the wind farm already exists - is
to simply turn off individual turbines that are known to be a problem at times
when the risk of mortality is high. Some of the most recent work suggests that
this can be done without a huge loss of revenue to the energy producer, so this
is probably often a very plausible solution.
Other cases where concerns have been raised include Attwater's prairie-chicken
in the US, white-tailed eagles in Scotland, and golden eagles along the
Appalachian chain. Typically, the problems are likely to be acute only for
pretty rare species that are concentrated in a fairly small area. In contrast,
there is very little evidence that wind farms are likely to affect populations
of song birds and unless there is a truly massive increase in the number of
turbines it is hard for me to see that they could have a serious impact at the
population level. Certainly, there are much larger threats out there - habitat
loss continuing to be the biggest for most species (and yes, wind farms
contribute to habitat loss too - but not nearly as much as many other forms of
development). Bats are perhaps another issue, as they seem more seriously
affected than birds, but I've yet to see a careful assessment of how wind power
ranks relative to other sources of energy for bats either.
One other line of evidence that might be of interest, is that a few years ago
when the Cape Wind project was under discussion, Mass Audubon put a lot of time
and resources into researching the issue of offshore wind farms to determine
what stance they should take as an organization. I know some of the people
involved with this process, and they took the issue very seriously. Moreover,
they were very aware that if they did not get the science right, it could really
hurt their organization, and they did a very careful job as a result. Their
conclusion - I think to the surprise of some of the people involved - was on
balance broadly positive (albeit with certain caveats, e.g., relating to
siting). More info on that here:
http://www.massaudubon.org/news/index.php?id=317&type=news.
So, as we they say in the ecology business "it's complicated" and to paraphrase
one of my favorite quotes - for every complex problem there is a simple answer
... and it is wrong. At a personal level my view is that every form of power
production causes problems of which killing birds is just one. But, of all the
options I know of, wind power is (mostly) at the benign end of the spectrum.
And for what it is worth, when my family had the chance to switch to a power
supply that comes from largely renewable sources, we took it.
Chris
Chris Elphick
Storrs, CT
elphick at sbcglobal.net